In these pilot, double-masked, randomized, multi-center studies, participants will receive monthly bevacizumab injections for the first three months, followed by PRN dosing. In addition, participants will take an oral dose of 100 mg of minocycline or placebo twice daily for 24 months. During each monthly visit, participants will have their visual acuity measured and will undergo OCT testing to measure retinal thickness. At the Month 3 visit and thereafter, participants will be evaluated for improvement and worsening and will be eligible for additional bevacizumab treatment and/or investigational product depending on which criteria they fulfill. Additionally, at Month 12, participants will also be evaluated for no improvement. The primary outcome is the difference in mean change in best-corrected visual acuity (BCVA), as measured in ETDRS letters, between the minocycline and placebo groups in the study eye at 12 months compared to baseline. Secondary outcomes include the difference between the minocycline and placebo groups in the number of intravitreal bevacizumab injections between 12 and 24 months and baseline, changes in mean macular sensitivity as measured by microperimetry at 3, 6, 12, 18 and 24 months compared to baseline, the mean change in BCVA at 24 months compared to baseline, changes in retinal thickness as measured by OCT at 6, 12, 18 and 24 months compared to baseline, number of participants improving 1 logOCT scale step at 12 and 24 months compared to baseline, as well as changes in fluid leakage in the macula as demonstrated by fluorescein angiography at 12 and 24 months compared to baseline. Safety outcomes include the number of participant withdrawals, the number and severity of systemic and ocular toxicities and the number of adverse events. BRVO and CRVO studies are designed similarly but are separate clinical studies as they each have their own natural history course. We therefore want to keep them separate as we compare responses to investigative drug. The studies have been expanded to include two sites in the UK. One site in the UK has started recruiting patients and has active study patients, the other site is activating shortly.